Effect of Deformation Strengthening and Phase Reversion Grain Refinement Strengthening on Corrosion Resistance of Fe-18Cr-8Ni Steel
Cold rolling and reverse phase transformation are the main methods to enhance the yield strength of austenitic stainless steel.Therefore,the effect of deformation strengthening and grain refine-ment strengthening on the microstructure and corrosion behavior of Fe-18Cr-8Ni austenitic stainless steel was characterized by SEM,TEM,EBSD,electrochemical workstation and other technical character-ization means.The results show that the deformation strengthening and the inverse phase transformation induced grain refinement strengthening could enhance the pitting resistance of austenitic stainless steel in 3.5％NaCl solution,grain refinement led to an increase in grain boundary density,which promote the diffusion rate of Cr at grain boundaries,thereby improving the stability and compactness of the passiv-ation film.After sensitization treatment,deformation strengthening and inverse phase transformation in-duced grain refinement strengthening could enhance the intergranular corrosion resistance of austenitic stainless steel.The appearance of Cr-depletion zone around chromium carbide precipitates will deterio-rate the intergranular corrosion resistance of the steel,while the rapid diffusion of Cr in ultrafine grain/fine grain structure will promoted the rapid healing of the passivation film on the Cr-depletion zone,thus the intergranular corrosion resistance of the steel may be improved.
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